NSF Convergence Accelerator Track J: Aqua Sacs for Sustainable Agriculture in a Changing Climate

气候变化强调了全球水资源的可获得性和日益严重的水资源稀缺性，特别是在干旱和半干旱地区。情况只会恶化，导致更严重和更频繁的干旱，随后是洪水，耕地减少，粮食不安全加剧。需要更有效的灌溉系统，特别是大豆、小麦和甘蔗等水分密集型作物。添加到土壤中的水凝胶通过吸收和保持水分并在土壤干燥时释放水分来减少灌溉频率。它们可以改善土壤的水物理性质，如孔隙度，并可以减少侵蚀和径流，从而减轻洪水的影响。水凝胶的功能是地下带有渗透膜的小水容器，可以提高微生物的活性、生长和利用率。目前，市场上销售的水凝胶大多是合成的聚丙烯酸酯和聚丙烯酰胺，这是以石油为基础的材料，不利于大规模农业的生态友好。一些半合成的淀粉基聚合物也是可用的。然而，一种更好的替代方案是可能的。以藻酸盐为基础的水凝胶已被证明在控制土壤水分以促进植物生长方面是有效的。在这个项目中，我们介绍了生态友好型水容器Aqua SAC，这是一种基于藻酸盐的水凝胶，可以生产各种图案，如片状或网状。渗透膜可以通过结合表面的钙形成，使它们在功能上类似于合成水凝胶。此外，在土壤中添加藻酸盐水凝胶可以刺激微生物活动，从而产生微生物生物量和多样性，藻酸盐的生物降解可以促进土壤健康，进而导致作物增产。海藻酸盐是从海藻中提取的，海藻可以可持续地养殖，同时提供一系列环境效益。海藻是一种零投入作物，不需要使用化肥、杀虫剂或淡水。相反，海藻从周围水域吸收多余的营养物质，包括溶解的氮和二氧化碳，这有助于对抗富营养化和气候变化。因此，Aqua SAC的发展将有助于增加对水产养殖海藻的需求，从而有利于陆地和海洋环境的农业和土壤健康。这个合作项目旨在了解和开发工业化步骤，以实现商业规模的Aqua SAC生产。开发的技术允许生产成卷的藻酸盐水凝胶，可以各种图案的片状或网状形式部署到田间，可用作从土壤水化到食品保鲜等应用的添加剂材料。从实验室到工业规模的扩展需要了解海藻养殖、藻酸盐提取、水凝胶优化和田间表现。从这些步骤中获得的信息将为我们提供必要的要素，以创建商业模式并寻找工业合作伙伴，以便在工业规模上生产和分销Aqua SAC。具体地说，我们将寻求：1)确定最大限度提高国内藻酸盐产量和质量的海藻品种和种植区；2)改进藻酸盐提取和水凝胶生产方法，以最大限度地减少废物产生；3)优化水凝胶膜的吸水性和保水性；以及4)进行田间测试，以了解水凝胶在实际农业条件下的性能。所有步骤都将在循环经济模式下制定，以最大限度地减少对环境的影响。该项目将被照片记录下来，并被拍摄下来用于公共传播。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Climate change has stressed the availability of global water resources and increased water scarcity, particularly in arid and semiarid regions. The situation will only worsen, leading to more severe and frequent droughts followed by flooding, decreasing arable land, and increasing food insecurity. A more efficient irrigation system is needed, especially for water-intensive crops, such as soybeans, wheat, and sugarcane. Hydrogels added to soil reduce irrigation frequency by absorbing and retaining water and releasing it when the soil dries. They improve the hydro-physical properties of the soil, such as porosity, and they can reduce erosion and runoff and thereby mitigate the effect of flooding. Hydrogels function as small water containers in the ground with osmotic membranes that increase microbial activity, growth, and performance rate.Currently, most of the hydrogels on the market are synthetic polyacrylates and polyacrylamides, which are petroleum-based materials and not ecologically friendly for large-scale agriculture. Some semisynthetic starch-based polymers are also available. However, a better alternative is possible. Alginate-based hydrogels have been shown to be efficient in controlling soil moisture for plant growth. In this project, we introduce the ecologically friendly water container Aqua Sac, an alginate-based hydrogel that can be produced in various patterns such as sheets or meshes. Osmotic membranes can be formed by binding calcium at the surface, making them similar in function to synthetic hydrogels. Moreover, adding alginate hydrogels to soil can stimulate microbial activity, which generates microbial biomass and diversity, and the biodegradation of alginate can contribute to soil health and, in turn, leads to increased crop production. Alginate is extracted from seaweeds, such as kelp, which can be sustainably farmed while providing a suite of environmental benefits. Seaweeds are a zero-input crop that does not require the use of fertilizers, pesticides, or fresh water. Rather, seaweeds extract excess nutrients from the surrounding waters, including dissolved nitrogen and carbon dioxide, which helps to combat eutrophication and climate change. Thus, the development of Aqua Sac will benefit agriculture and soil health on land and the marine environment by helping to increase the demand for aquacultured seaweeds. This collaborative project aims to understand and develop the industrialization steps required to produce Aqua Sac at a commercial scale. The technique that was developed allows the production of alginate hydrogel in rolls that can be deployed to the field in the form of sheets or meshes of various patterns that can be used as an additive material for applications ranging from soil hydration to food preservation. The scaling from a laboratory to an industrial scale requires an understanding of seaweed farming, alginate extraction, hydrogel optimization, and field performance. Information obtained from these steps will give us the elements necessary to create a business model and seek industrial partners for the production and distribution of Aqua Sac on an industrial scale. Specifically, we will seek to: 1) identify seaweed species and growing regions that maximize domestic alginate production and quality; 2) refine methods of alginate extraction and hydrogel production to minimize waste production, 3) optimize the hydrogel membrane for water absorption and retention, and 4) conduct field tests to understand the performance of the hydrogel under actual agricultural conditions. All steps will be developed within a circular economy model to minimize environmental impact. The project will be documented by photo and filmed for public dissemination.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.